Large exciton binding energies in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>MnPS</mml:mi><mml:mn>3</mml:mn></mml:msub></mml:math> as a case study of a van der Waals layered magnet
Magdalena Birowska, Paulo E. Faria, Jaroslav Fabian, Jens Kunstmann
Abstract
Stable excitons in semiconductor monolayers such as transition-metal dichalcogenides (TMDCs) enable and motivate fundamental research as well as the development of room-temperature optoelectronics applications. The newly discovered layered magnetic materials present a unique opportunity to integrate optical functionalities with magnetism. We predict that a large class of antiferromagnetic semiconducting monolayers of the $M\mathrm{P}X{}_{3}$ family exhibit giant excitonic binding energies, making them suitable platforms for magneto-optical investigations and optospintronics applications. Indeed, our investigations, based on first-principles methods combined with an effective-model Bethe-Salpeter solver, show that excitons in bare Neel-${\mathrm{MnPS}}_{3}$ are bound by more than 1 eV, which is twice the excitonic energies in TMDCs. In addition, the antiferromagnetic ordering of monolayer samples can be inferred indirectly using different polarization of light.